1. Field of the Invention
The present invention relates generally to interconnecting two wiring ducts on opposite sides of a suspended ceiling.
2. Description of the Prior Art
The first duct is usually upstream of (i.e. above) the suspended ceiling and in the form of a tube located in the space above the suspended ceiling and containing the necessary electrical cables or conductors. The second duct is downstream of (i.e. below) the suspended ceiling, inside the room, and in the form of trunking, often referred to as a molding, designed to be installed against a wall of the room and taking over from the aforementioned tube as a means of routing the electrical cables or conductors.
In the usual way, the term xe2x80x9ctrunkingxe2x80x9d refers here to a wiring duct including, possibly in one piece, a base portion with an open cross section and a cover portion adapted to close the base portion.
The present invention is more precisely concerned with the connection to be made between the two wiring ducts for optimum continuity between them to protect and insulate the electrical cables or conductors.
The present invention relates more particularly to the situation in which this connection entails the use of an adapter including, on the one hand, a back portion which has an opening at one end into which a first of the wiring ducts is inserted and to the other end of which the other wiring duct can be butt-jointed, this back portion having a reference plane intended to be level with the lower face of the suspended ceiling and, on the other hand, a cover portion which at least partly covers the back portion.
At present the adapter is entirely below the reference plane, i.e. the suspended ceiling.
Consequently the wiring duct above the suspended ceiling has to pass through it, extending to a greater or lesser degree into the room below.
The diameter of the tube usually constituting this wiring duct varies from one installation to another. It follows that the adapter, which matches to the diameter of the tube, can be large compared to the duct inside the room, which is generally required to be of discreet appearance.
In some cases, for reasons of standardization, the back portion of the adapter must be adapted to receive the largest diameter tube.
In other words, at present it is the transverse dimension of the largest possible upstream wiring duct that imposes the size of the back portion of the adapter.
Accordingly, the adapter, all of which projects into the room, is relatively bulky, to the detriment of its esthetics, even though in some installations at least its dimensions may be larger than strictly necessary.
The object of the present invention is to provide an adapter which has the advantage of minimizing this disadvantage.
According to the invention, the opening in the back portion of the adapter is upstream of the reference plane, and therefore of the suspended ceiling, so that the corresponding wiring duct does not need to pass through the suspended ceiling, or at least completely through it.
Accordingly, only the upstream part of the back portion must be suitable for the largest possible transverse dimension of the wiring duct and its downstream portion, which is the only portion that can be seen in the room, can be smaller and therefore more discreet, to the benefit of its esthetics.
Features and advantages of the invention will emerge from the following description which is given by way of example only and with reference to the accompanying diagrammatic drawings.